CHATACTERIZNTIAN OF SOME IRAQI ASPHALTS. II. NEW FINDINGS ON THE PHYSICAL NATURE OF ASPHALTENES

ABSTRACT

Uapcur pressure csmometry (UPO) and viscometric technique were used to reveal the true molecular weight of asphaltenes and the degree of association in solvent of different polarities at different temperatures. The number average malecular weight of unassociated asphaltenes was found to be 935 g/mcl. In n' trobenzene at 120 C. The degrees of association were determined from UPO in benzene at 37, 45, 60 C, in chlorobunzene at 37, 45, 60 and 90 C. in THE at 37, 45, 60 C and in nitrobenzene at 90 C. The degree of association determined by ulscometric method at 37, 45 and 60 C, in these soluents were found to be in approximate agrement with that found bv UPO. Data derived by means of ulscometric and osmometric methods consolidated the recognition that asphaltenes could be similar to macro-molecules structurally.